FRITZ!Box reports "A microwave was detected"

The speed of the wireless connection (WiFi) to the FRITZ!Box displayed by wireless devices such as computers, smartphones, or tablets, is significantly lower than the data rate allowed by the wireless standard 802.11n. The following message is displayed in the event log of the FRITZ!Box:

Cause

The FRITZ!Box detects sources of interference, for example a microwave in the frequency range around 2.45 GHz. To ensure stable wireless connections, the FRITZ!Box automatically reduces the channel bandwidth from 40 MHz to 20 MHz. Although wireless devices then display a lower data rate, the user data rate is increased because there is less interference and the wireless connection is no longer affected by constant retransmissions.

Note:All instructions on configuration and settings given in this guide refer to the latest FRITZ!OS for the FRITZ!Box.

Simply proceed as described below. After each measure, check whether the problem persists.

1 Finding the ideal location for the FRITZ!Box

If possible, position the FRITZ!Box in a central location. FRITZ!Box has omnidirectional antennas. The wireless signal is therefore emitted spherically in all directions.

Do not position the FRITZ!Box directly in the corner of a room.

Position the FRITZ!Box so that it is as unobstructed as possible, i.e. not directly in back of or under an obstacle such as pieces of furniture or a heater.

Position the FRITZ!Box as high in the room as possible, for example on a shelf.

Position the FRITZ!Box so that there are as few obstacles as possible between it and the wireless devices. Even small objects in the immediate vicinity of your FRITZ!Box can greatly reduce the coverage area of the wireless signal. Metallic objects or objects containing water, for example radiators, refrigerators, or even houseplants, significantly reduce the quality of the wireless signal.

Position the FRITZ!Box away from other radio transmitters, for example microwaves, wireless speakers, or Bluetooth devices.

2 Selecting the best wireless channel

Click the link "Show disturbances to wireless network" in the "Wireless Environment" section.

Use the diagram to determine which channel in the lower frequency range is least affected by other wireless networks and interference.

Enable the option "Adjust radio channel settings" in the "Radio Channel Settings" section.

From the drop-down list "Radio channel", select the wireless channel that was the least affected.

Click "Apply" to save the settings.

If the issue with your wireless connection still occurs, repeat steps 3 - 7 with a wireless channel in the middle and then with one in the higher frequency range. Once you have finished testing, use the wireless channel that was least affected by disturbances.

Important:The diagram of the wireless environment only reflects the current situation! The allocation of the frequency band can change significantly over the course of the day because many wireless networks are turned on when in use. Therefore, check several times to see which wireless channels are least affected by interference.